Rashba interaction and local magnetic moments in a graphene-Boron Nitride heterostructure by intercalation with Au

TL;DR

This study demonstrates that intercalating gold in a graphene-Boron Nitride heterostructure induces Rashba spin-orbit interaction, magnetic moments, and novel magnetotransport phenomena, persisting near room temperature.

Contribution

It reveals that gold intercalation creates a two-dimensional interface with spin-splitting and magnetic properties, advancing understanding of spin-orbit effects in van der Waals heterostructures.

Findings

Gold at the interface is two-dimensional.

Rashba spin-splitting of ~25 meV observed.

Giant negative magnetoresistance up to 75%.

Abstract

We intercalate a van der Waals heterostructure of graphene and hexagonal Boron Nitride with Au, by encapsulation, and show that Au at the interface is two dimensional. A charge transfer upon current annealing indicates redistribution of Au and induces splitting of the graphene bandstructure. The effect of in plane magnetic field confirms that splitting is due to spin-splitting and that spin polarization is in the plane, characteristic of a Rashba interaction with magnitude approximately 25 meV. Consistent with the presence of intrinsic interfacial electric field we show that the splitting can be enhanced by an applied displacement field in dual gated samples. Giant negative magnetoresistance, up to 75%, and a field induced anomalous Hall effect at magnetic fields < 1 T are observed. These demonstrate that hybridized Au has a magnetic moment and suggests the proximity to formation of a collective magnetic phase. These effects persist close to room temperature.